Liquid fuel combustion chambers for jet-propulsion engines, gas turbines, or other purposes



s. k. JACKSON Sept. 24, 1957 LIQUID FUEL COMBUSTION CHAMBERS FOR JET-PROPULSION ENGINES, GAS TURBINES, OR OTHER PURPOSES Filed Dec. 14, 1954 atent ()fifice 2,807,316 Patented Sept. 24, 1957 LIQUID FUEL COMBUSTION CHAMBERS FOR JET-PROPULSION ENGINES, GAS TURBINES, OR OTHER PURPOSES Squire R. Jackson, Burnley, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England Application December 14, 1954, Serial No. 475,157

1 Claim. (Cl. 158-4) This invention relates to combustion chambers for jet propulsion engines, gas turbines, or other purposes, of the kind to which liquid fuel is supplied in the form of a spray directed towards the closed entrance end of the chamber, and to which air is supplied by a blower.

The object of the invention is to minimise or prevent formation of a carbon deposit on the central region of the said end of the combustion chamber, and to ensure rapid and intimate mixture of the air with the fuel.

The invention comprises the combination with the entrance end of the combustion chamber, of a short axially arranged cylindrical air duct extending upstream, and a swirling means adapted to impart a rotary motion to the air flowing into the duct.

In the accompanying drawing, Figure 1 is a longitudinal section of a combustion chamber provided with the invention.

Figure 2 is a sectional side elevation illustrating the invention to a larger scale than Figure 1, and Figure 3 is a cross section on the line 3-3, Figure 2.-

Referring to the drawings, the combustion chamber a may be of any convenient construction having an entrance end of hemispherical or other curved or conical form. The said end 12 may be constructed from two (or more) overlapping metal parts forming narrow air inlet passage (or passages) cthrough which air can flow from a surrounding air jacket d over the inner surface of the said end, the air being supplied under pressure from a blower.

The outer side of the said end of the combustion chamber has secured to it a hollow nose piece e constructed from overlapping sheet metal parts forming between them a narrow air passage f through which air can flow into the nose piece from the air jacket.

On the axis of the entrance end of the combustion chamber is secured a short cylindrical air duct g directed towards the incoming air stream. The end of the duct remote from the combustion chamber may be wholly closed by an end plate h, or alternatively the said plate may be perforated. Around the said end of the duct are formed air entrances i which receive air under pressure from the interior of the nose piece. The said entrances are formed by flat blades 1' so disposed as to form between them a plurality of tapering air passages, each of which terminates in a narrow exit k at the periphery of the duct, the passagesi being adapted to direct the air into the duct tangentially, and so form a rapidly swirling air stream in the duct. At the exit end of the duct is formed an outwardly flared flange m adapted to direct the issuing air in the form of a thin stream over the inner surface of the combustion chamber end. The said flange may be arranged to form with the adjacent part of the combustion chamber the air passage 0 above mentioned which receives air from the region around the duct.

By the provision of an air-swirling means as above described on the axis of the entrance end of the combustion chamber, the deposition of carbon on the said end, and particularly its central part, from the fuel spray directed by the fuel supply nozzle n towards the said end, can be effectively prevented or minimised in a simple and reliable manner.

In the above described construction, theamount of air supplied to the combustion chamber through the duct g is restricted to that required to obviate carbon deposits, the greater part of the air required for combustion of the liquid fuel being supplied from the jacket d through apertures as 0 (Figure 1).

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

A liquid fuel combustion apiparatus comprising in combination a combustion chamber provided at one end with an axial air entrance, and at positions intermediate its ends with lateral air-admission openings, a fuel supply nozzle arranged in said chamber to direct fuel in the form of a spray towards the air entrance end of said chamber, a short cylindrical air-admission duct extending axially and outwardly from the air entrance end of said chamber, and having a plurality of air-entrance passages arranged tangentially around the exterior of the outer end of said duct to direct air under pressure into said duct, and so form in said duct a rapidly swirling air stream which has access through said duct to said chamber, the inner end of said duct being flared outwardly, an airjacket surrounding said chamber and duct, and having at the end adjacent to said duct an inlet through which air under pressure is admissible to said jacket, and a hollow nose piece enclosing said duct and the air entrance end of said chamber for directing the greater part of the air admitted under pressure to the jacket inlet into the part of said jacket surrounding said chamber, said nose piece being constructed from overlapping metal parts forming between them, at a position intermediate the ends of said nose piece, a narrow passageway through which some of the air admitted to the jacket inlet can flow into the interior of said nose piece for admission to said air-entrance passages around the outer end of said duct.

References Cited in the file of this patent UNITED STATES PATENTS 

